Microwave System; Capacitor; Testing A Capacitor; Combination Hv/Filament Transformer - TurboChef Eco Service Manual

Microwave System

The Eco oven utilizes a single magnetron system.
In the case of an over-current situation, the F3 fuse
will blow, shutting off the system immediately.
NOTE: The Eco oven utilizes a single magnetron
system.
This section contains information about the
following components:

• Capacitor

• Filament/High-voltage transformer
• High-voltage diode
• Magnetron
• Stirrer motor and assembly
• Waveguide
This section also contains procedures for:

• Testing a capacitor

• Testing a filament portion of the transformer
• Testing a high-voltage diode
• Wiring the high-voltage transformer
• Testing a magnetron for an open/shorted filament
For information on accessing and removing parts,
see the Appendix.
Capacitor
The capacitor value will vary by country. Reference
the schematic (page 63) for proper values.
Testing a Capacitor
DANGER: Never attempt any measurement
of the capacitor while it is enabled. Lethal
voltage will be present. Measure only in
compliance with these procedures.
1. Disconnect the oven from the power source.
2. Fully discharge the capacitor.
3. Isolate the capacitor from the circuit.
4. Check for an open or shorted capacitor by
placing ohmmeter leads between the capacitor
terminals:
• Escalating ohm readings = capacitor OK
• Constant infinite resistance = capacitor open
• Constant very low resistance = capacitor
shorted
5. If the capacitor is not open or shorted, set the
meter to measure capacitance and again place
the leads between the capacitor terminals. The
meter reading should equal the label value, plus
or minus 4% maximum. If not, replace the
capacitor.

Combination HV/Filament Transformer

The control energizes the filament portion of the
transformer in combination with the high-voltage
(step up) portion of the transformer.
When in operation, the filament portion of the
transformer supplies approximately 3.15 VAC at 10
amps to the magnetron filament. The high-voltage
portion of the transformer supplies the high voltage
for the voltage doubler circuit.
The filament/high-voltage transformer is controlled
via the K2 Anode relay.

Wiring the Transformer

DANGER: Never attempt to wire or measure
the secondary voltage values of the transformer.
Lethal voltage will be present.
The proper reinstallation of the transformer is
critical. Upon removing the transformer, make sure
to note where each wire was installed. Refer to the
oven schematic (page 63 for wiring detail.
With the microwave system energized, the volt
meter will read the incoming voltage (different
readings for different electrical installations).
The wiring must be correct prior to returning the
oven to service, as the voltages must be:
• North America: 208 VAC between 1 & 2 and
240 between 1 & 3.
• International: 230 VAC between T1 & T2
NOTE: The orange wire must always go to
terminal 3 on US models.
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